Interrupter switch usable as a sectionalizer in high voltage systems

ABSTRACT

A high voltage switch has a set of main contacts and two auxiliary interrupter devices. One of the interrupters is used for interrupting loop currents, while the other is used for interrupting charging currents in a power system. The choice of which interrupter is used is made automatically dependent upon the magnitude of recovery voltage across the switch.

United States Patent inventors Edward R. Krajewski Shaker Heights; I Elmer L. Luehring, Cleveland Heights, both of, Ohio Appl. No. 20,563

Filed Mar. 18, 1970 Patented Aug. 31, 1971 Assignee Joslyn Mfg. and Supply Co.

Chicago, Ill.

INTERRUPTER SWITCH USABLE AS A SECTIONALIZER IN HIGH VOLTAGE SYSTEMS 6 Claims, 3 Drawing Figs.

US. Cl. 200/ 146 Int. Cl. H0lh 33/59 Field of Search 200/146 [56] References Cited UNITED STATES PATENTS 2,955,181 10/1960 Luehring....; 200/146 3,027,439 3/1962 Upton, Jr. et a]. 200/146 X 3,070,680 12/1962 McBride et a1. 200/146 3,171,004 2/1965 Luehring 200/146 Primary Examiner-Robert S. Macon Attorney-Richard l-l. MacCutcheon' ABSTRACT: A high voltage switch has a set of main contacts and two auxiliary interrupter devices. One of the interrupters is used for interrupting loop currents, while the other is used for interrupting charging currents in a power system. The choice of which interrupter is used is made automatically dependent upon the magnitude of recovery voltage across the switch.

, Pmiminweausn 3,602,668

SHEET 1 UF 2 INVENTORS EDWA R. KRAJEWSKI BY ELME .LUEHRING mzzmamm ATTORNEY PATENIED was 1 1971 sum 2 or 2 m VEL. =4

HV (23, 24) oR E-R vA 3M. s6 (25,26) Fl .2 4| 2 g DA(I4,I5) mm 7 (27) ARC HORN l E/E l A(2l,l4) MAIN CONTACTS l .4 1 MUZJS) 29.2 s sw', 3J2 |2,|3 2M4 |4,|5 l7 23,24 25,26 25,26 sEOuENcE NO. N A DA B HV FULL CL CLSD CLSD OPEN CLSD OPEN OPEN OPEN OPENING 2 OPENs v CLOSES CLOSES a OPEN OPENs CLSD CLSD i 4 OPEN OPENs ARCS 5 OPENS CLOSES e OPEN CLSD OPENS OPENs FULLOPEN 7 a u u n ()PEN I OPEN CLOSING 8 CLOSES 9 CLSD CLOSES CLOSES l0 CLDSES OPENs was BACKTO l- INVENTORS EDWARD R. KRAJEWSKI BY ELNER L. LUEHRING ATTORNEY INTERRUPTER SWITCH USABLE AS A SECTEONALKZER IN HIGH VOLTAGE SYSTEMS BACKGROUND OF THE INVENTION This invention relates to high voltage switch apparatus and has particular significance in connection with the provision of plural switch capabilities in a single switch assembly as for use in power system sectionalizing.

it may be that a part of our invention or discovery is recognition of the fact that most switching required for the operation and maintenance of a high voltage power system can be done at relatively low power levels compared to circuit or system capacity. in the steady state operation of a system, switches are seldom required to interrupt the flow of power in a manner which simultaneously causes large changes of both voltage and current.

Heretofore, three different classes of switches known as interrupter Switches have been classified as:

1. Load interrupter Switches,

2. Low Current interrupter Switches,

3. Loop Current interrupter Switches.

Although in each class there is competition, patentwise as well as in the field, three patents assigned to the assignee of the present invention may be used to typify these three classes. 1. A Load interrupter Switch is described and claimed in u.s. pat. No. 2,955,181 which was issued Oct. 4, 1961, on an application filed by E. l... Luehring. Such switches have the advantage of being capable of causing changes of both rated voltage and rated current simultaneously, but they are relatively expensive, particularly for the higher voltage interrupting requirements.

2. A Low Current interrupter Switch for use on high voltage systems is described and claimed in U.S. Pat No. 3,217,115 which issued Nov. 9, 1965, on the application of H. C. Kaplan. Such a switch has the advantage of very high speed separation of arching contacts, and can cause voltage changes equal to rated system voltage, but can only interrupt relatively low currents without permanent damage.

3. A Loop Current interrupter Switch can be considered as described and claimed in U.S. Pat. No. 3,171,004 which issued Feb. 23, 1965, on an application of Luehring. The device of that patent, which was filed for in 1961, was more complex than that of the present invention. Additionally, Loop Current interrupter Switches are restricted to circuits having very small (e.g., percent of rated) voltage change coincident with switching.

An object of the present invention is to provide inexpensive means for overcoming the above-mentioned difficulties.

Another object of the invention is to provide improved equipment capable of switching a high voltage power system when either the current or the voltage change is, nonsimultaneously with the other, equal or near rated values.

Another object is to combine the utility of the Low Current interrupter Switch with that of the Loop Current interrupter Switch.

An additional object is to preclude the need for full rated load interrupter switches when switching for maintenance while at the same time obviating the need to instruct human operators as to a necessary sequence of switching different types of interrupter switches.

BRIEF DESCRlPTiON OF THE DRAWING Other objects and advantages will become apparent and the invention better understood from consideration of the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of a portion of an interrupter switch shown part open and having associate parts according to an embodiment of the invention;

FIG. 2 is a schematic diagram and "accompanying table showing typical operating sequence steps for apparatus asin FIG. 1; and

FIG. 3 is a simplified one-line circuit diagram provided for illustrating utility and advantage of switches such as that previously shown.

DESCRlPTiON OF PREFERRED EMBODIMENTS Many issued patents (including said U.S. Pat. Nos. 3,217,115, 3,171,004, and 2,955,181) show or assume cooperable moving and fixed insulators for a high voltage switch. in the present case FIG. 1, the moving insulator is not shown, but its operation can be assumed to be the same as in U.S. Pat. No. 2,955,181 and as it turns in one plane it moves a switch arm and blade in another plane to cause cooperation with a fixed insulator, i0, and parts it carries. As shown, insulator i0 supports a contact bracket and terminal member 11 which in turn carries a set of fixed main switch contacts 12 cooperable with a main switch blade 13 moved by the movable insulator. For closing, the switch blade 13 swings downward in an arc and then, as is quite usual, a final rotation may be used to increase contact pressure for the fully closed position. Upon opening, the main switch blade swings upward to vertical position.

Somewhat like the arrangement in U.S. Pat. No. 2,955,181 (FIG. 2) a driver assembly 14 projects from the end of the main switch blade 13. Driver 14 is conductive (e.g., of a copper carbon material) and is designed to engage an actuator arm 35. As in U.S. Pat. No. 2,955,181, the actuator arm rotates a portion of a covered mechanism, indicated generally at 16, with the mechanism designed to cause opening of interrupter contacts, 117, which are located within an insulating housing 118 which may be used for preserving a vacuum in which the contact 17 operate, opening as the actuator arm I5 is lifted by driver 14. As by using the toggle described and claimed in U.S. Pat. No. 2,955,181, the contact opening action can be made independent of the speed at which actuator arm 25 is lifted, the parts being adjusted so that opening will occur at a certain position of arm 15 so that adequate electrical clearance exists between parts on either side of (and electrically in parallel with) the loop interrupter contacts 17.

The mechanism 16 also provides spring bias to actuate arm 15 to return it (downward in the drawing) to a resilient stop 19 after driver 14 disengages during upward" movement in the opening mode. During the closing mode of operation, the driver i4 presses past the actuator arm l5; then the stop 19 propositions the arm for subsequent opening operation. Loop interrupter contact closing occurs when the arm 15 is released (during opening). Thus when actuator arm 15 is in its rest position (on stop 19), the loop interrupter contacts are closed.

As described and claimed in Luehring and Poe Pat. No. 2,915,61 1 of Dec. 1, 1959, and assigned to the assignee of the present invention, there can be as many insulated contactcontaining housings (l8) mechanically in tandem and electrically in series, or in parallel, as desired, but an advantage of the present invention is that even for the most rigorous operating conditions not so many such housings need to be used and for the present case FIG. 1, only one such housing 18 is assumed (e.g., per phase), and it is supported on a conducting material bracket 20 electrically connected to the terminal l1, and supported by the fixed insulator Ni.

An arc born 21 is fixedly supported as by the conducting bracket 20, and the arc horn is in contact with the driver 14 when the main switch blade is in engagement with main contacts 12. Contact between arc horn 2i and driver 14 is eliminated after the driver l4 makes contact with the actuator arm 115.

in the drawing FIG. 1, an insulating section 22 is supported with respect to fixed insulator 10. At the top of insulating section 22, a hook latch 23 is arranged to catch and temporarily restrain a resilient conductive rod 24. As described in U.S. Pat. No. 3,217,115, the whiplike rod 24 is mechanically and electrically connected with respect to the switch blade 13 and it may also cooperate with an energy absorbing buffer affixed to blade 13.

In accordance with one aspect of the present invention, a pair of conductive horns 25, 26 are affixed to end fittings of insulating section 22 in such manner as to form a spark gap. When a breakdown (sparking) is caused between the ends of horns 25 and 26 in nearest proximity, a circuit is formed from contact support bracket 11 through horns 26, 25 latch 23, rod 24 and thus blade 13. The gap between horns 25 and 26 is adjusted to electrically break down at a smaller voltage than the recovery voltage rating of the interrupter contacts .17. With this arrangement, if, during an opening sequence of blade 13 (as shown in FIG. 1), an increasing voltage appears across interrupter contacts 17, it will be limited by the flashover of the gap between horns 25 and 26.

As a further improvement of function, the spark gap 25-26 may be shunted by a resistor 27 (see FIG. 2) having a negative resistance characteristic, with respect to voltage across the resistor. Such resistors are well known as varistors. This shunting improvement reduces the recovery voltage across switch elements by absorbing transient electrical energy and trapped charges, and with this modification it is feasible to rate the interrupter apparatus at almost twice the system voltage limiting the switch not so equipped.

In the FIG. 2 schematic diagram and in the FIG. 2 Table of Sequence Steps below the schematic, like parts are like numbered as in FIG. 1. In the schematic, paths for the loop current mode of operation are indicated by heavier lines, while for the low current mode of operation both the heavy and the lighter line paths are to be considered.

Although, from the standpoint of both economics and operation, it might be best to construct the overall switch as shown in FIG. 1 or FIG. 2, other switch constructions can function similarly. For example, if the cooperating arc horn 21 were eliminated the change would not destroy function, but it would probably shorten the life of the equipment.

From an inspection of FIG. 1 or of the Table of FIG. 2, it is apparent that the main switch opens (Sequence Step 2) and then the arc horn is disengaged (Step 3). Next is the opening of loop interrupter contacts 17. If the voltage appearing across interrupter contacts 17 immediately after their separation is greater than the breakdown setting of gap 25, 26, then, as a part of Step 4, the circuit is automatically transferred (by sparking of the gap 25, 26) to the low current interrupter comprising resilient rod 24 and latch 23. While the exact sequence may be varied, in the illustrated embodiment (FIGS. 1 and 2), continued movement in the opening direction of main blade 13 causes disengagement of driver-actuator l4, 15 (Step The actuator arm 14 then returns to its rest position determined by stop 19 of FIG. I. As blade 13 moves further to open position, resilient rod 24 is deflected by the restraining action of latch 23 until it eventually pulls free from the latch 23 (Step 6) and moves rapidly to its normal position parallel to blade 13. After the separation of rod 24 from latch 23, blade 13 is moved to a vertical position and adequate separation exists between conductive parts supported by the fixed insulator and other conductive parts supported by the movable insulator which is not shown.

The one line diagram of FIG. 3 points up the utility and advantages of the switch of FIGS. 1 and 2. Such a switch is assumed employed at each of the locations 3136. Power sources are represented at 37, 38', and a distribution feeder system at 39. The overall system may continue, as indicated by the dashed line 40, to include similarly connected elements, distribution systems, power sources, etc.

Under normal operating conditions, all switches are closed and transmission lines between 32 and 33 and between 34 and 35 are energized, with current and power flowing through the transformer tap, 41. But if, for reasons of performing maintenance, the line from 34 to 35 is to be deenergized, and all power supplied through the line from 32 to 33, switches 34 and 35 must be opened. The first switch opened will interrupt load current flow but the voltage appearing across the switch will be but a small percentage of system voltage, and the interruption will occur as indicated in the schematic of FIG. 2 and in the Sequence Table of FIG. 2 for loop Current Switching. The line element form 34 to 35 will thus be energized from one end only, and the current flow through the switch still closed will be low, being only that required by the distributed line capacitance. To deenergize the line from 34 to 35, the second switch will be opened and the operation will be that depicted in FIG. 2 for Low current Switching.

Since the switches 34, 35 are identical, the matter of which switch is opened first is of no consequence to the operator, even though the performance of each is automatically different from that of the other, each being automatically suited to the requirements of the system. Thus the operator who may not be familiar with the stations, and cannot usually simultaneously view switches at opposite ends of a transmission lipe, is relieved of a decision, but even more important are the-large cost savings made possible by having each main switch made automatically sensitive to the way it must be used/ Modifications are possible. Thus it would be within the invention to mount the spark gap mechanically and electrically across the loop interrupter housing 18 and arrange the low current interrupter latch 23 mechanically and electrically on housing 16 (or, alternatively, on actuator arm 15) thereby eliminating insulating section 22, for while we have illustrated and described particular embodiments, various modifications may obviously be made without departing from the true spirit and scope of the invention which we intend to have defined only by the appended claims taken with all reasonable means for opening low currents and constituting another part of the second-mentioned circuit electrically in parallel with the main contact means.

2. In a high voltage switch of the type having first or main contact switch means (M) which includes a switch blade, a second or interrupter switch means (B) comprising at least one interrupter device having separable contacts and a conductive operating arm electrically and mechanically associated with movement of the switchblade and for separating the interrupter contacts, the separable contacts being electrically arranged in a circuit which parallels the circuit of the main contacts while mechanical arrangement is such that the interrupter contacts open after the main contacts open on opening, 7

the combination of a third switch means (l-IV).which comprises an element having one end affixed with respect to the main switch blade and constituting one part of a second interrupter, and a spark gap (SG) electrically connected in series with said third switch means, the series arrangement of third switch means and spark gap being electrically connected in parallel with the first switch means while mechanical arrangement is such that the interrupter of said third switch means opens after opening of the first switch means and after opening of the second switch means during opening.

3. In a high voltage switch, the arrangement as in claim 2 further characterized by the spark gap being shunted by a varistor. t

4. In a high voltage switch, the arrangement as in claim 2 further characterized by a resilient element separating ele-.

ments of the second interrupter at high velocity compared to velocity of separation of the first switch means.

5. In a high voltage switch, the arrangement as in claim 2 further characterized by commutating contacts (A) protecting the first switch means, which commutating contacts separate after the first switch means opens but before the second switch r 3,602,668 -s v 6 means opens and before the third switch means opens during further characterized by th second switch means comprising opening iEEHPiYEEFP;

6. In a high voltqgo switch the arran go noni as in claim 2 

1. In a high voltage switch, the combination of main contact means, a relatively reduced voltage interrupter means for opening loop currents and which is electrically connectable in parallel with the main contact means, a relatively high voltage and relatively high velocity interrupter means for opening low currents and which constitutes a part of a circuit electrically in parallel with the main contact means, and a high voltage breakdown device connected in series with said high velocity means for opening low currents and constituting another part of the second-mentioned circuit electrically in parallel with the main contact means.
 2. In a high voltage switch of the type having first or main contact switch means (M) which includes a switch blade, a second or interrupter switch means (B) comprising at least one interrupter device having separable contacts and a conductive operating arm electrically and mechanically associated with movement of the switchblade and for separating the interRupter contacts, the separable contacts being electrically arranged in a circuit which parallels the circuit of the main contacts while mechanical arrangement is such that the interrupter contacts open after the main contacts open on opening, the combination of a third switch means (HV) which comprises an element having one end affixed with respect to the main switch blade and constituting one part of a second interrupter, and a spark gap (SG) electrically connected in series with said third switch means, the series arrangement of third switch means and spark gap being electrically connected in parallel with the first switch means while mechanical arrangement is such that the interrupter of said third switch means opens after opening of the first switch means and after opening of the second switch means during opening.
 3. In a high voltage switch, the arrangement as in claim 2 further characterized by the spark gap being shunted by a varistor.
 4. In a high voltage switch, the arrangement as in claim 2 further characterized by a resilient element separating elements of the second interrupter at high velocity compared to velocity of separation of the first switch means.
 5. In a high voltage switch, the arrangement as in claim 2 further characterized by commutating contacts (A) protecting the first switch means, which commutating contacts separate after the first switch means opens but before the second switch means opens and before the third switch means opens during opening.
 6. In a high voltage switch, the arrangement as in claim 2 further characterized by the second switch means comprising a vacuum switch. 